There is some server side verification, mostly around checking that the dependencies all exist, the file isn't too large, etc. But 99% of the testing happens on

There is some server side verification, mostly around checking that the dependencies all exist, the file isn't too large, etc. But 99% of the testing happens on the client. Eg: https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a7334357d573a1486d4fa60f1/src/controllers/krate/publish.rs#L386-L437 https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a... https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a7334357d573a1486d4fa60f1/src/controllers/krate/publish.rs#L325 https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a... https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a7334357d573a1486d4fa60f1/src/controllers/krate/publish.rs#L278 https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a... https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a7334357d573a1486d4fa60f1/src/views/krate_publish.rs#L16-L36 https://github.com/rust-lang/crates.io/blob/58e505f2abdabd6a...